This study reviewed financial assessment methods, financial estimation models, and considerations to make in introducing a financial estimation model, for the Basic Livelihood Security System(BLSS). In the long term, this study is aimed at establishing a financial estimation model for the social security system. The financial assessment frame was analyzed in three aspects, including efficiency, effectiveness and equity, following a proposal made by international organizations such as the OECD and the World Bank and preceding studies. The BLSS has reduced the poverty rate for all households in Korea by 8% point on average for three years covered by the study. The poverty rate for households with single parents or members with disabilities has dropped by minimum 13% and maximum 20% after the introduction of the BLSS. The efficiency of poverty reduction was measured to be 78% on average for three years covered by the study. (The rest omitted)